Light emitting diodes (LEDs) have recently been attracting attention as a light. LEDs, considering their low power consumption and long lives, have a low load on the environment compared to conventional lights such as fluorescent lamps. Particularly, linear LED lights are expected to be more used in the future.
Since LEDs are a point light source, various attempts have been made to enable a transparent pipe including LED light sources to give an impression of a surface light source such as a conventional fluorescent lamp.
The attempts are, for example, incorporating a light diffusing agent into the materials (e.g. glass, resin) of lighting covers and transparent pipes, applying a light diffusing agent onto lighting covers and transparent pipes, and winding a sheet or film having a light diffusing function onto lighting covers and transparent pipes.
Patent Literature 1, for example, discloses a light transmission and diffusion filter for lighting, which contains uniformly diffused quartz glass fine particles and a light diffusing material such as titanium dioxide, silica, and calcium in a light transmitting resin. The light transmission and diffusion filter for lighting described in Patent Literature 1 greatly scatters broken fragments when broken by unexpected accident including falling of the transparent pipe, and is therefore unsatisfactory in terms of ease of handling and safety.